
The CR123A battery is a non-rechargeable 3V lithium battery with physical dimensions of 34.5 x 17 mm (H x D). The average CR123A battery has a 1500 mAh capacity, a nominal voltage of 3.0 volts, and a cutoff voltage of 2.0 volts.
Because the dimensions of a 2CR5 battery are somewhat larger than two CR123A cells stacked side by side, certain gadgets have a specific battery holder that allows the user to power the device with either one 2CR5 battery or two CR123A batteries.
Because the CR123A battery is also available as a rechargeable CR123A battery (also known as RCR123A battery), two RCR123A batteries might theoretically be used to power devices that need 2CR5 batteries.
In real life, two RCR123A batteries feature a nominal voltage of 7.2 - 7.4 volts and this voltage difference between 2CR5 and two RCR123A batteries of 1.2 - 1.4 volts can damage or even destroy some sensitive devices.